Method and means for propagating a mass



METHOD AND ll/IEAlli PROPAGATING A Yusuf A. Yoler, Schenectady, N. Y.,assigner to General Electric Company, a corporation of New YorkApplication March 1, 1956, senat No. 570,001

Claims. (cl. 89-7) This invention generally relates to improvements inthe method and means for generating and applying energy, and morelparticularly to improvements in the method and apparatus forpropagating a mass down the length of an enclosure at great speed.

The generation of strong shock waves within shock tubes and the ring ofprojectiles out of guns are customarily performed by suddenly releasingenergy to generate an expanding mass of gas or vapor Ibehind aprojectile or shock wave. Otherwise stated, this generation of force andpower is initiated by Va single sudden release of energy, by Vsuch meansas an explosion or the like, resulting in the rapid expansion of the gasbehind the projectile or behind the shock wave. However, with thistechnique, which may be termed a single shot of energy release, thepressure 4and `temperature of the gas initially builds up to a highvalue and then decays at a rapid rate asthe projectile or 'shock wavetravels down the length of an enclosure; and, consequently, the maximumspeed of propagating the projectile or the shock wave is 'lower thancould be obtained if the pressure and temperature could be maintained ata high level behind the projectile or shockwave.

In accordance with the present invention, a unique method and apparatushave been Vevolved for maintaining such a high pressure and temperaturelevel continuously behind the projectile or shock wave as it passes downthe length of an enclosure. This is performed by a continual andsuccessive multiple discharge of energy into the enclosure in acontrollable manner and in a proper sequence behind the projectile orwave to maintain a nearly uniform high energy level in the expandinggas. By maintaining this high level of energy, rather than employing asingle release of energy whose level decays at a rapid rate, it isevident that the projectile is maintained at a uniformly highacceleration and progressively increases speed as it travels down thelength of the tube at a considerably greater rate than possible with asingle energy release of the same magnitude.

It is accordingly one object of the present invention to provide animproved method and apparatus for propagating a shock wave or forpropelling a projectile at greater speeds than heretofore attainable.

A second object of the invention is to provide an improved method andapparatus for successively releasing energy in a spaced manner within anenclosure forvmaintaining controllable and distributed energy level oraccelerating force along `the length of the enclosure.

Another object of the present `invention is `to provide a more ecientmethod and apparatus for applying electrical energy to accelerate `amass.

Still a further object of the present invention is to provide a lessexpensive and simpler method and apparatu for accelerating masses.

Other objects and many attendant advantages of this invention will bemore readily comprehended to those skilled in this art upon a detailedconsideration of the States Patent r"ice following specification takenwith the accompanying drawings wherein:

Fig. l is a diagrammatic sketch depicting one preferred manner ofautomatically releasing electrical energy in sequence down the length ofan enclosure in accordance with one preferred process of the presentinvention, and

Fig. 2 is a View similar to Fig. 1 illustrating one preferred apparatusfor performing the technique of Fig. l.

Referring now to Fig. 1 for a consideration of one preferred method andapparatus in accordance with the present invention, there is shown, insection, an elongate tube 10 that is sealed at the left-hand portion andopen ended at the right, and preferably formed of electricallynonconducting material in a cylindrical shape as shown. A series ofspaced conducting electrodes 12-18, inclusive, that are electricallyinsulated from one another, are distributed along the length of thetube. An additional starter electrode 1 1 is positioned at the sealedleft-hand portion of the tube, as shown. `l'inergizing each adjoiningpair of these electrodes 11-18, inclusive, is a separate high voltagesource of electrical energy 19-25 inclusive, with each source having itsterminals energizing adjacent electrodes through a suitable electricalnetwork `for controlling the time constant of any electrical arc thatmay discharge through that electrode.

The starting direct current source 19 energizing the end electrode 11and the first electrode 12 through a normally open switch 34, is of alarge venough direct current voltage to initiate an arc dischargethrough the gas, such as air, within the tube when the switch 34 isclosed. However, the potentials across the remaining electrodes 12-18,inclusive, are not suiciently large for generating an arc through thegas within the tube.

To initiate the operation, switch 34 is closed connecting source 19across end electrode l11 and first electrode 12. This high voltagegenerates an arc within the tube, in the pattern generally representedby the line 35; imparting or dumping great heat and electrical energyinto the tube and generating a great expansion of gases which form ashock wave. Concurrently the electrical energy poured into the tube andthe rapid heating of the vapor causes the gas to ionize.

As the shock wave is accelerated down the length of the tube, thisionized gas behind it travels between the tirst pair of electrodes 12and 13 lowering the electrical resistance of the gas between electrodes12 and 13 and enabling an arc to be generated across these electrodes asgenerally represented by the lines 36. This arc feeds an additional joltof electrical energy into the tube at a position spaced from the firstelectrical discharge. The time constants of each arc discharge and theelectrical energy imparted by the arcs are controlled to maintain theenergy level constant as the shock wave travels down the length of thetube, thereby continually renewing the energy level in the tubeimmediately behind the shock wave and preventing any `decay in thisenergy level such as would normally result from a single shot discharge.

Thereafter, as the shock wave travels past each pair of the electrodes,the ionized gas continually moving behind comes in contact with'eachsuccessive pair of electrodes thereby continually imparting jolts ofenergy into this tube in such amanner as x12o-maintain the energycontent ata uniformly 'high lpredetermined level and `obtain Within thetube to provide this force.

the desired great speed of propagation of this shock wave down the tube.This permits the addition of energy in a continual and successive mannerinto the tube enabling a much greater energytobe generated within thetube at spaced intervals along the tube thanY could be possibly obtainedwith the. single shot method and .apparatus employing a tube ofcomparabledimensions.

The time constants of the successive discharge paths are so adjustedthat the rst discharge'is preferably. the longest and each succeedingdischarge continues to supply current until the work of the shock waveis completed.

In the event it is desired to employ this unique process for propellinga projectile at high speeds down the length of this tube, the projectile42 is preferably mounted upon a suitable shoe or piston-like device 43,as shown in Fig. 2. In this case, each successive arc between theelectrodes maintains the high pressure and temperature of the expandinggases behind the projectile at a desired high level as the projectile ispropagated down the length of the tube. Maintaining this temperature andpressure at this high level, maintains the force accelerating thisvprojectile down the length of the tube at a desired high level and, terefore, propels this projectile at relatively high accelerationthroughout its travel in the gun. Consequently, being driven at arelatively high acceleration, the velocity with which this projectiletravels progressively increases as it passes down the length of thetube, and the muzzle velocity or speed of projectile ejection from theend of the tube is a function of the length of the tube and the maximumenergy that can be generated This operation is to be contrasted with theconventional single shot tiring of projectiles, since in the single shotor conventional methods the energy forcing the projectile out of thetube ldecays as a function of this length. In accordance with thepresent invention, on the other hand, the force propelling theprojectile down the tube is maintained at a high level and .theprojectile is, therefore, maintained at a high acceleration whereby itsvelocity increases at a considerably greater rate than in prior devices.

As shown by one preferred structure in Fig. 2, the enclosure it! may bepreferably formed of a single elongate tube 50 or of a series ofseparate cylindrical insulating sections 50 connected in sequence byconducting ring-like electrodes 51 having a substantially T-shaped crosssection. The sealing means at the lefthand end of the tube 50 may be thestarting conducting electrode 52 which is suitably joined to the rstnonconducting cylindrical section or tube to provide a iluidtight seal.It is evident that the thickness and strength of the cylindrical tube 50or the thickness and strength of the individual sections 50 andconnections to the conducting rings holding these sections together mustbe so designed as to withstand the extreme internal temperatures andpressures generated for propagating the shock wave or the projectile 42.

Rather than employing separate direct current voltage sources toenergize adjoining ring like electrodes, as shown in Fig. l, it ispreferred to employ a series of capacitors 53-59, inclusive adapted tobe charged by a single high voltage direct current source 60 throughsuitably selected charging resistors 61-67, inclusive, whose values areadjusted to provide the desired time constants. The discharging of thesecapacitors through inductors 26-32, inclusive, as discussed abovecontrol the time constant of the electrical energy passing into the tubeas arcs are successively generated between adjoining electrodes.

if this preferred method is employed in a gun to propel a projectile 42,the projectile structure, as shown, is preferably formed of theprojectile itself 42 suitably ,mounted upon a sabot or shoe 43 in theform of a cup shaped piston, as shown. This enables the pressure VWithinthe tube to exert the maximum force against the projectile shoe. I fdesired, the projectile 42 and shoe 43 may be disengageably connected sothat the projectile is separated from the shoe upon leaving the tubeenabling the shoe to fall away and .the projectile to be directed alonga ballistic trajectory at the desired high speed.

Thus by means of the present invention, it is observed that there isprovided a more efcient means for imparting great amounts of energywithin a closed container than could heretofore be obtained by employingthe single shot of energy techniques. This is accomplished bysuccessively generating energy in a spaced manner along the Length of anenclosure whereby as the shock wave or propelled element travels downthe length of this enclosure, the forces propagating Ithis wave orprojectile do not decay but are continually maintained at highpressure-temperature conditions throughout the length of the tube.

lt is believed well known to those skilled in the art that thiselectrical a-rc discharge technique provides a much greater propagatingspeed than does the Vusual chemical reactions, since greatertemperatures, more uniform heating and greater control of the release ofenergy are obtained within the tube than can be obtained with the usualchemical reactions. t is further evident to those skilled in the artthat this means for generating and applying greater usable energy can beobtained automatically or in a self-triggering manner that is quitesimple and inexpensive since the propagated element or shock wave,itself, triggers or switches the various energy gene-rating means -toimpart energy to the tube in a desired sequence thereby requiring noadditional switching or timing mechanism. Additionally, if desired, moreelaborate external circuitry may be employed to trigger the arcdischarges in a different sequence or to provide greater control of thetime constants.

Although but one preferred method and apparatus have been disclosed andillustrated as required by the .Patent Laws it is believed evident tothose skilled in the art that many changes may be made in the shape andstructure of the cylindrical tubes, ring electrodes, capacitor chargingand discharging elements, or any of the other preferred details shownand described above without departing from the spirit and scope of thisinvention. Additionally it is believed evident that means other than thegeneration of an initial electrical arc may be used lto initiateoperation since the exhaust gases from chemically generated explosioncould likewise be used to trigger the succession of arcs along thecontainer. Consequently it is intended that this invention is to belimited only in accordance with the following claims appended hereto.

What is claimed is:

l. The method of sequentially generating energy to propagate a shockwave or propel a projectile down the length of an elongate enclosurecontaining a gas comprising the steps of: generating a first dischargeat one end of the enclosure to greatly heat and ionize this gas settingit in motion down the length of the enclosure, and utilizing themovement of this ionized gas to sequentially trigger a successive seriesof electrical arcs spaced from each other in time and position down thelength of said 'en-closure, said ionized gas being employed to lower theelectric resistance of the gas as it travels down the length of theenclosure thereby enabling the sequential initiation of said electricalarc discharges.

2. The method of propagating a shock wave or propelling a projectiledown the length of an elongate nonconducting container enclosing asubstantially non-conducting gas comprising the steps of: energizingspaced portions of said container with voltage potentials ofinsuflicient magnitude to generate an electric are through the gas inits un-ionized state, releasing energy at one end of said containertogreatly heat and ionize the gas placing it in motion in a wavetraveling down the length of the container, said movingionized gasinitiating a sequential series of electrical arcs as said ionized gaspasses :each ofsaid spaced portions, whereby the electric energy .lijklay..

being generated within said gas and behind said moving wave ismaintained at a substantially high level.

3. The method of propagating a shock wave or propelling a projectiledown the length of an elongate nonconducting container enclosing asubstantially non-conducting gas comprising the steps of: applyingvoltage potentials along adjoining portions of said container havinginsufficient magnitude to generate an electric arc through the enclosedgas, generating a first energy discharge at one end of said container togreatly heat and ionize the gas placing it in motion in a wave travelingdown the length of the container, said moving ionized gas initiating asequential series of arcs as said ionized gas passes each of said spacedadjoining portions, whereby the electric energy being generated withinsaid gas and behind said moving wave is maintained at a desired highlevel.

4. The method of generating a shock wave traveling at extremely highspeed down the length of a non-conducting container housing asubstantially nonconduct ing gas comprising the steps of: producing aseries of spaced electrical fields within said gas in a direction alongthe length of said container whose eld strength is just insuthcient toinitiate ionization and arcing through said gas, producing a rst energydischarge at one end of the container to greatly heat and ionize the gasthereafter initiating a shock wave down the length of said container andsetting the ionized gas in motion behind the shock wave, whereby as saidionized gas sequentially moves through each of said electrical fields,it initiates a successive series of arc discharges through the gascontinually renewing the energy behind said shock wave to maintain ahigh energy level propagating said wave throughout the length of thecontainer.

5. The method of propelling a projectile at progressively increasingspeed down the length of an elongate housing of electrically insulatingmaterial containing said projectile and air comprising the steps of:applying large direct current potentials at spaced portions along saidhousing to produce a series of electrical fields within said gas alongthe length of the housing producing an initial energy discharge `withinsaid housing behind said pro jectile to greatly heat, expand, and ionizethe air thereby propelling said projectile down the length of theconrainer and permitting said ionized air to `expand and travel behindthe projectile, said expanding ionized air operating to trigger each ofsaid applied potentials in sequence, to produce an automatic successionof electrical arcs within said housing as the projectile passes each ofsaid spaced portions.

6. In an apparatus for generating enengy to propel a shock wave orprojectile down the length of an elongate t container housing a gas, anelongate non-conducting container having one end thereof sealed and theother end open to air, a series of conducting electrodes positioned in aspaced manner within said container, means for applying direct currentpotentials to said electrodes to produce spaced electrical ields withinsaid container, and means for generating an energy discharge in thevicinity ot the sealed end of the container to greatly heat, expand andionize the air and set this air in motion down the length of thecontainer, whereby as said ionized air passes said spaced electrodes, ittriggers a sequential series of electrical arc discharges within thecontainer.

7. In an apparatus for sequentially generating energy to propagate ashock wave or propel a projectile, an elongate non-conducting hollowtubular member having one end thereof sealed and the other end open toair, a series of conducting electrodes positioned within said member andspaced along the length of said member, means for applying directcurrent potentials across each adjoining pair of electrodes to producespaced electrical elds within said member of insufcient magnitude toionize the air, and means for producing a iirst electrical arc dischargewithin said member and in the vicinity of the sealed end of the memberto greatly heat and ionize the air and set this ionized air in motiondown the length of the member, whereby as said ionized air passes eachof said spaced electrical lields, it lowers the electrical resistance ofthe gap between said electrodes and triggers the generation of anelectrical arc therebetween, thereby enabling the successive generationof electrical arcs down the length of the member maintaining the energylevel behind the traveling ionized gas at a high level.

8. in the apparatus of claim 7, a plurality of electrical reactancenetworks, each in circuit with the means for applying direct currentpotentials to adjoining pairs of electrodes, and each network adapted tocontrol the magnitude and time phase generation of current through theseelectrodes forming the arc discharge.

9. In an apparatus for sequentially generating energy to propel a shockwave or a projectile, an elongate nonconducting tubular member havingone end thereof sealed and the other end open to air, a series ofconducting rings within said member and spaced from one another, meansfor applying direct current potentials to energize each adjoining pairof rings thereby to produce a series of spaced electrical fields Withinsaid member, and means for ionizing the air within said member in thevicinity of the sealed end thereof and setting said ionized air inmotion down the length of the member, whereby as .said ionized airtraverses each pair of said spaced rings it triggers an electric arcdischarge thereacross, enabling the generation of a successive series ofelectrical arc discharges down the length of said member.`

l0. In the apparatus of claim 9,-'a plurality of electrical reactancenetworks, a different one of said networks being in circuit with each ofsaid pairs of ring electrodes, and each of said networks adapted tocontrol the magnitude and time phase of electrical currents passingthrough said ring electrodes during the arc discharge thereacross.

No references cited.

